Although cardiac catheterization and angiography remain the standard tests for assessment of many hemodynamic and anatomic abnormalities of the heart, they have often been supplanted by echocardiography and other imaging modalities for the initial and serial evaluation of many conditions. Nonetheless, “invasive” procedures (ie, those involving the use of intravascular and intracardiac catheters), when appropriately employed, remain invaluable in the management of most patients with congenital, valvular, and coronary heart disease.

Right heart catheterization is convenient to perform in the laboratory, at the bedside, or in the operating room. It allows measurement of right atrial, right ventricular, pulmonary artery and pulmonary capillary wedge pressures (the latter an indicator of left atrial pressure), oxygen saturation, and cardiac output. These data may diagnose intracardiac shunts, physiologically significant pericardial disease, and right-sided valve lesions and can distinguish between cardiac and pulmonary disease. Hemodynamic monitoring may be very helpful in the assessment and treatment of shock, heart failure, complicated myocardial infarction, respiratory failure, and postoperative hemodynamic instability.

However, this procedure is not without risk - complications include pneumothorax, bleeding, arrhythmias, pulmonary artery rupture, pulmonary emboli, and infection. Therefore, the role of this procedure remains unsettled, though the available evidence indicates that appropriate use of pulmonary artery catheters to guide therapy may reduce morbidity. Bedside echocardiography can be used to assess left ventricular function, pericardial effusion, valvular abnormalities, intracardiac shunts, and pulmonary artery and central venous pressures when the need for continuous monitoring is not anticipated.

Left heart catheterization is performed to assess the cardiac valves and left ventricular function. Mitral stenosis and aortic stenosis are quantified by measuring the pressure gradients across the valves and, taking flow into account, the estimated valve areas. Mitral and aortic regurgitation are assessed semiquantitatively from contrast injections in the left ventricle and aorta, respectively. The ejection fraction and regional wall motion are assessed by contrast left ventriculograms. The severity of stenotic valve lesions can usually also be measured by echocardiography, though regurgitant lesions may be more difficult to quantify. Left ventricular function can also be assessed by echocardiography and nuclear scintigraphy. Therefore, the main indications for left heart catheterization are for confirmation of the need for valve surgery and for obtaining coronary angiograms. Increasingly, the catheterization laboratory is used for performing coronary interventions.

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Scanlon PJ et al: ACC/AHA guidelines for coronary angiography. A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on Coronary Angiography). Developed in collaboration with the Society for Cardiac Angiography and Interventions. J Am Coll Cardiol 1999;33:1756.